1. Field of the Invention
The present invention generally relates to surgical cannulas and bio-sensors for minimally invasive surgery. More particularly, the present invention relates to devices and techniques for guiding surgical instruments, injectable matter, diagnostic devices, and/or bio-sensors through complex trajectories.
2. Discussion of the Related Art
Minimally invasive surgical (MIS) techniques have revolutionized medicine in recent years by enabling surgical treatment without the massive trauma typically resulting from traditional open surgery. MIS techniques have enabled physicians to gain access to and perform interventions in anatomical regions previously unreachable under open surgical techniques. Further, MIS techniques have greatly reduced the trauma associated with surgery, thereby reducing surgery-related complications and expediting post-surgery recovery. Without viable MIS alternatives, surgery in confined spaces within the body (especially the head and neck) require large incisions and destructive dismantlement of healthy bone, skin, and muscle structure simply to enable tool access to the surgical site.
Related art MIS tools include rigid laparoscopic devices, which require a great deal of open space both inside and outside the body to perform dexterous motions in surgery. This requirement for open space generally precludes the use of laparoscopic devices in many types of surgery. Other related art MIS tools include flexible shape memory alloy devices, in which the shape of the device can be changed be applying heat to the shape memory alloy as the device is guided within a patient. One problem with such a device involves the unintended application of heat to the surrounding tissue. Another problem is that the thermal time constants of the shape memory alloy require considerable time (as long as several seconds) for appropriate heat to be applied and subsequently dissipated. The delays imposed by these thermal time constants limit the applicability of such MIS devices.
Other related art MIS devices include teleoperated surgical robots that typically have 5-10 mm diameter straight and rigid tools, which have a wire-actuated or push rod-actuated wrist. A problem with such related art surgical robots is that they are constrained to pivot at the body entry point and do not have the dexterity to maneuver through curved trajectories and around obstacles once within the body. By being constrained to pivoting at the body entry point, such surgical robots are generally unsuitable for complex surgical procedures, such as fetal surgery within the womb. In the case of fetal surgery, at least two pivot points are required: one at the mother's skin, and another at the wall of the uterus.
Surgical interventions involving the head and neck are particularly challenging, even with the advent of MIS techniques. For example, treatment of lesions at the base of the skull typically involve MIS devices being endoscopically inserted through the nose. Because related art MIS devices lack the dexterity to bend around and through small openings in the sinus cavities, many healthy tissue and bone structures, such as the nasal turbinates, must be removed to enable the MIS devices to access various surgical sites, including the base of the skull. Regarding nasal turbinates, their normal functions are to purify air and to aid in olefaction. Once removed for the purposes of gaining access to surgical sites, they cannot be reconstructed in such a way that their function is restored. Two exemplary surgical sites that cannot be reached using related art straight MIS devices include areas behind the carotid arteries (near the base of the eye) and the frontal sinus cavities, which involve reaching around a bone located directly behind the bridge of the nose.
Other examples of a surgical procedures in which related art MIS devices lack dexterity is lung surgery and throat surgery. Regarding lung surgery, a related art bronchoscope generally can only reach about ⅓ of the lung's interior. Currently, there are no low-risk methods of removing biopsy samples or directly treating cancer deeper within the lung. Further other related art methods of lung biopsy and treatment involve inserting needles, which incurs a substantial risk of complications, including lung deflation. Regarding throat surgery, lesions located deep within the throat are very difficult to access without large incisions. The large incisions are typically made to enable suturing. The throat itself as an avenue for suturing would mitigate the need for large incisions. However, related art MIS devices lack the dexterity to travel long distances through a laryngoscope, which typically has an 11 mm diameter.
Accordingly, what is needed is a surgical tool that has the dexterity to be maneuvered around anatomical features in order to gain access to otherwise unreachable surgical sites. Further, what is needed is a surgical device that can be guided through free space within a cavity, such as the sinuses, throat, and lungs, as well as through a tissue medium.